Pocket Protecting Retainable Cutter Bit

ABSTRACT

Pocket protecting retainable cutter bits used on various mining, excavating, and foundation drilling tools and equipment are disclosed. The invention includes a combination of one or more free spinning wear rings axially mounted in recessed portions of the cutter bit shank and a groove and snap ring retainer. The wear rings are tapered on at least one end to assist in installation and designed to compress as the cutter bits are installed into cutter bit pockets. These wear rings are designed to protect the inside surface of the pocket by acting as a barrier between the spinning cutter bit and the stationary inside surface of the pocket. The cutter bit shank is longer than the cutter bit pocket and when installed passes through the pocket and extends past the axial length of the pocket. A flange is included with the cutter bit to protect the outer surface of the pocket.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a nonprovisional of U.S. Patent Application No. 61/054,150 filed on May 18, 2008, the entirety of which is hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was not federally sponsored.

BACKGROUND OF THE INVENTION Field of the invention

This invention relates to the general field of drilling, and more specifically toward pocket protecting retainable cutter bits used on various mining, excavating, and foundation drilling tools and equipment. The goal of the current invention is to prevent the common problems associated when using said equipment, specifically the wear of cutter bit pockets and the loss of cutter bits. The invention is a combination of one or more free spinning wear rings axially mounted in recessed portions of the cutter bit shank and a groove and snap ring retainer. The wear rings are designed to compress as the cutter bits are installed into cutter bit pockets. These wear rings are designed to protect the inside surface of the pocket by acting as a barrier between the spinning cutter bit and the stationary inside surface of the pocket. The wear rings can be made of wear resistant materials, preferably hardened metal, although it is envisioned that hard plastic, graphite, composite materials, and rubber could be used. These wear rings are split lengthwise to allow them to compress when inserted into the cutter bit pockets. The wear rings are tapered on at least one end to assist alignment and installation into cutter bit pockets. The cutter bit shank is longer than the cutter bit pocket and when installed passes through the pocket and extends past the axial length of the pocket. A radial snap ring groove is cut into the exposed end of the cutter bit shank and when a snap ring is installed provides a failsafe method of retention.

While digging and excavating has occurred throughout ancient times, it was only in the early 1900s that Howard Hughes invented the first carbide roller bits. These bits dramatically improved production and have since undergone substantial improvements in technology. While improvements have been made in the field of cutting tools and equipment, a major problem has remained unsolved: when using heavy equipment there is a massive amount of abrasion and wear that occurs and most of the wear and subsequent damage occurs at the cutter bits and the pockets that hold them in place. Cutter bits are designed to spin inside the pockets that hold them so both the cutter bits and the pockets will wear evenly as they cut through dirt and rock. The problem is that while the cutter bits spin they wear out the inside surface of the pockets that hold them in place. Cutter bits are usually easy to replace when worn out, but the pockets are difficult and time consuming to replace because they are usually set at specific cutting angles and are welded into place.

The prior art has several examples of attempts to resolve the problem, including the inventions of U.S. Pat. No. 4,844,550 to Beebe, U.S. Pat. Nos. 5,088,797 and 5,302,005 to O'Neill, and U.S. Pat. No. 5,628,549 to Ritchey, et al. These patents attempt to reduce wear, but in reality, mainly serve to hold the cutter bit inside the pocket with spring loaded friction. Because the wear and tear on the cutter bits is quite substantial, the use of prior art devices have continued to result in high friction between the cutter bit and the pocket thereby producing heat and mechanical grinding between the cutter bit and pocket with a corresponding loss of holding power. The prior art also contains cutter bits with dual retainer systems. The main problem with these products is that they do not protect both the inside and outside of the pocket. The current invention solves this problem by providing a cutter bit with a substantial flare, or flange, that protects both the inside and the outside of the pocket.

These references have proven to be ineffective in numerous situations as cutting tools experience normal use vibrations and impacts. These vibrations and impacts often loosen the spring loaded rings and compromise their holding power. Subsequently, cutter bits frequently fall out of their pockets causing immediate damage to the unprotected surfaces of host tools. Tool repairs and loss of production are prevalent especially when excavating hard and highly abrasive materials. The prior art also teaches loose wear parts that need to be installed and removed before and after installing and removing cutter bits. These extra steps require more time and effort, and any replacement of a cutter bit also presents the possibility of injury or death to the mechanic. The machines that use cutter bits to bore into the ground are quite large and powerful, and a standard augur can weigh several tons, thereby creating an inherently dangerous situation whenever a worker is called upon to replace a cutter bit or perform other maintenance on the machine.

It is also noteworthy that by increasing the lifespan of a cutter bit and reducing the number of serviceable parts, the invention decreases the frequency and cost with which welders have to work upon the machines. This is beneficial in several ways. First, welding on a machine is an inherently dangerous activity. The less frequently welding has to be done, the lower the risk of injury and death. Second, qualified welders can be expensive. Thus, a user of the invention will pay less than would a company using the prior art cutter bits since less welding will be required. Third, having a machine out of service can cost the company that owns the machine several thousand dollars for each day of inactivity. In remote locations where it is not feasible to weld, the machine may have to be removed from the worksite and transported to a more convenient location—all for a $50 cutter pocket. Obviously it is highly beneficial to have machines stay out on the job for longer periods of time, and having a cutter bit which protects both the inside and outside of the pocket, is easily replaced, and decreases the frequency with which the pockets need to be replaced.

Thus there has existed a long-felt need for a cutter bit that can protect both the inside and outside of the pocket, ensure failsafe retention and be easy to install and replace. The current invention provides such a solution by having a pocket-protecting and retainable cutter bit that is easy to install and replace, the goal of which is to prevent the common problems associated when using excavating equipment, specifically the wear of cutter bit pockets and the loss of cutter bits through its unique flange shape and wear rings. The invention includes a combination of one or more free spinning wear rings axially mounted in recessed portions of the cutter bit shank and a snap ring retainer groove. The wear rings are designed to compress as the cutter bits are installed into cutter bit pockets. These wear rings are designed to protect the inside surface of the pocket by acting as a barrier between the spinning cutter bit and the stationary inside surface of the pocket. The wear rings can be made of abrasion-resistant materials, preferably hardened metal, oil impregnated bronze, or other self-lubricating material. These wear rings are split lengthwise to allow them to compress when inserted into the cutter bit pockets. The wear rings are tapered on at least one end to assist alignment and installation into cutter bit pockets. The cutter bit shank is longer than the cutter bit pocket and when installed passes through the pocket and extends past the axial length of the pocket. A radial snap ring groove is cut into the exposed end of the cutter bit shank and when a snap ring is installed provides a failsafe method of retention.

SUMMARY OF THE INVENTION

It is a principal object of the invention to provide a new pocket protecting, retainable cutter bit by which a cutter bit manufacturer or consumer can extend the life and value of their tooling and avoid costly and time consuming replacement of lost cutter bits and worn cutter bit pockets. These cutter bits can be made in many different shapes and sizes to protect the inside and outside of the pocket depending on the material being cut and excavated.

It is another object of the invention to reduce the need to replace lost cutter bits by providing a failsafe retention method.

It is an additional object of the invention that the cutter bit will have the wear rings pre-installed on its shank to make it easy to install and remove from pockets.

It is a further object of the invention that the cutter bit will have one or more wear rings depending on the shape of the pocket.

It is also an object of the invention that the wear rings can be made in various shapes to protect more than one surface at a time.

It is an additional object of the invention that the wear rings be made of wear resistant materials such as hardened steel, self lubricated oil impregnated bronze, or others that prevent wear and reduce friction.

It is also an object of this invention that the wear rings will be split lengthwise to allow their bodies to compress not only for ease of manufacturing, but also to allow for the wear rings to compress when installed in the pockets.

It is also an object of this invention to accommodate many different tooth shapes and sizes in order to cut various types of materials.

It is a further object of the invention to provide a cutter bit that protects both the inside and outside of the pocket.

It is another object of this invention to provide a cutter bit that does not require a separated wear sleeve; rather it is self contained within the cutter bit and protects the pocket without the use of a separate device such as a sleeve.

It is a final object of this invention to provide a cost effective solution that is easy to manufacture and use in the field.

The current invention provides a cutter bit that protects and reduces wear of the inner and outer surfaces of the pocket. The flange of the cutter bit protects the outer surfaces of the pocket while the split wear ring of the cutter bit allows the cutter bit to rotate within the pocket while reducing wear on the inner surface of the pocket. Prior art teaches using multiple devices to ineffectively reach the same goal, such as cutter bits with one or more sleeves that are separately inserted into the pocket, whereby the sleeves must also be replaced as they are worn down.

The cutter bit of the current invention enables more efficient maintenance of drilling tools. Instead of installing and maintaining a cutter bit and a sleeve, the current invention only requires the cutter bit. The cutter bit itself is easily installed and replaced. The cutter bit shank is inserted into the pocket until it protrudes through the other side and then is locked in place using a snap-ring or other comparable means. Removal of the cutter bit is just as easy, whereby a user can remove the cutter bit by removing the snap-ring and then forcing the cutter bit out of the pocket. In desolate areas where maintenance is difficult, the current invention enables users to quickly, easily, and efficiently replace cutter bits without separately maintaining sleeves and while reducing wear on the pockets.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. The features listed herein and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a bottom perspective view of an auger, or host tool, with a plurality of cutter bits retained in pockets according to the current invention.

FIG. 2 is a side perspective view of a cutter bit according to the current invention;

FIG. 3 is a top view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a far side view thereof;

FIG. 7 is a front view thereof; and

FIG. 8 is a rear view thereof.

FIG. 9 is a side view of the cutting bit retained inside of a pocket.

FIG. 10 is a side view of another embodiment of invention where there are two wear rings.

DETAILED DESCRIPTION OF THE FIGURES

Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings.

FIG. 1 is a bottom perspective view of a host tool with a plurality of cutter bits retained in pockets according to the current invention. Each cutter bit is secured to the host tool inside of a pocket. The end of the cutter bit opposite of the flanged tooth extends through the pocket and through to the other side of the host tool, whereby the portion of the cutter bit that extends beyond the other side of the host tool includes a snap ring groove (not shown in this figure) to secure the cutter bit within the pocket and to the host tool. As the host tool is rotated, the cutting bits dislodge and break apart the material to be excavated. Each cutting bit is allowed to rotate within its pocket thereby causing the cutting bit to wear evenly.

FIG. 2 is a side perspective view of an embodiment of a cutter bit according to the current invention. The cutter bit 20 includes a flanged tooth with a tooth 21 and a flange 27. As the host tool is rotated, the tooth 21 of the cutting bit dislodges and breaks apart the material to be excavated. The flange 27 of the flanged tooth protects the front surface of the pocket as the material is excavated. While a particular style of tooth of 21 is shown in this and other figures, other styles and shapes are possible and preferable depending on the material being excavated. Thus, other style and shapes for the tooth 21 are possible without departing from the scope of the current invention.

Next to the flange 27, there is a relieved shank surface 24 around which there is a split wear ring 25. The split wear ring 25 is axially mounted over and substantially surrounds the relieved shank surface 24 between a retaining shoulder 23 and the flange 27 of the flanged tooth. The split wear ring 25 has a resting outer diameter that is greater than the outer diameter of the retaining shoulder 23. A resting outer diameter is the outer diameter of the object while under no external forces. The pocket that holds the cutting bit 20 and secures it to the host tool should have an inner diameter that is slightly larger than the outer diameter of the retaining shoulder 23, and slightly less than the resting outer diameter of the split wear ring 25. There is a split in the split wear ring that allows the ring to compress to a smaller diameter, allowing it to be close-fitting within the inner wall of the pocket. When the cutting bit 20 is secured within the pocket, the split wear ring 25 is in constant contact with the inner surface or wall of the pocket while the retaining shoulder 23 is not. This allows the flanged tooth to rotate within the wear ring and prevent wear on the inner surface of the pocket.

It should be noted when viewing this figure that should even one of the many cutter bits fail, the entire machine will be shut down until the cutter bit is replaced. If it is determined that the pocket holding the cutter bit has been damaged to the extent that it has to be replaced, a welder must be brought in to fix the pocket. Thus, it should be seen that a cutter bit that not only resists wear better than the prior art, but also protects the pockets in a far superior manner to the prior art is an extremely significant improvement in the field. Statistics show that a cutter bit with a wear ring will last three to five times as long as a prior art cutter bit, and that a pocket into which only cutter bits with wear rings have been inserted will last approximately ten times as long as a pocket that has held prior art cutter bits. Since the average cutter bit costs around $25, and a pocket costs around $50 plus at least $250 in labor costs to replace, it should be obvious that the cost savings alone will be substantial.

The relieved shank surface 24 rotates against the inner surface of the split wear ring 25, and thus causes wear against these two surfaces instead of the inner surface of the pocket. To aid in the installation of the cutting bit 20 into the pocket, the split wear ring 25 includes a tapered side 26, which is located on the side closest to the retaining shoulder 23. As the cutter bit 20 is inserted into the pocket, the tapered side 26 of the split wear ring 25 comes in contact with the face of the pocket and causes the split wear ring 25 to compress slightly, thereby allowing the split wear ring 25 and the remaining portion of the cutter bit 20 to fit within the pocket up to the flange 27.

Continuing along the cutter bit 10 and after the retaining shoulder, there is a snap ring shaft 28 that leads to the snap ring groove 22. The snap ring grove 22 is designed to extend beyond the opposing side of the pocket and host tool. This allows a snap ring to attach around the snap-ring groove 22 to secure the cutter bit 20 within the pocket and to the host tool. While a snap ring groove 22 with a snap ring is a failsafe and preferable method for retaining the cutter bit within the pocket, other means of securing the cutter bit within the pocket are possible without departing from the contemplated scope of the current invention.

FIG. 3 is a top view of the cutter bit; FIG. 4 is a side view thereof; FIG. 5 is a bottom view thereof; and FIG. 6 is a far side view thereof.

FIG. 7 is a front view of the cutter bit clearly showing the different diameters of the flange 27 and tooth 21. FIG. 8 is a rear view of the cutter bit. The flange 27 is clearly shown as well as the diameters of the split wear ring 25, retaining shoulder 23, and snap ring shaft 28. As shown in this figure, the resting outer diameter of the split wear ring 25 is greater than the outer diameter of the retaining shoulder 23.

FIG. 9 is a side view of the cutter bit retained inside of a pocket. The pocket 30 itself is welded inside of the host tool (not shown in this figure). The pocket preferably has two inner diameters, a larger inner diameter closer to the tooth of the cutting bit and a smaller inner diameter further away from the tooth of the cutting bit. The tooth 21 extends beyond the pocket 30 and is used to dislodge and break apart the material that is to be excavated. The flange 27 has an outer diameter that is greater than the proximate inner diameter of the pocket 30 thereby extending over and protecting at least a portion of the outer surface of the pocket 30. The split wear ring 25 is secured between the flange 27 and the retaining shoulder 23 on the cutter bit 20. As shown in this figure, the split wear ring 25 is in close contact with the inner surface of the pocket 30. While the outer diameter of the split wear ring 25 is compressed slightly from its resting diameter to fit within the pocket 30, the inner diameter of the split wear ring 25 should still be greater than the outer diameter of the relieved shank surface (not clearly visible in this figure). This allows for the cutter bit to rotate within the pocket walls 30 and split wear ring 25, whereby the split wear ring 25 acts as a buffer between the relieved shank surface and the inner surface of the pocket 30. The retaining shoulder 23 should have a diameter that is less than the inner diameter at the location of the inner surface of the pocket 30 when the cutter bit 20 is secured to the pocket 30. However, because of the shape of the pocket, the retaining shoulder 23 may nonetheless come in contact with the inner surface of the pocket 30 from time to time as the cutter bit 20 moves within the pocket. The outer diameter of the snap ring shaft 28 should also be less than the diameter of the inner surface of the pocket 30 at that location. While it is preferable that the snap ring shaft 28 not come in contact with the inner surface of the pocket 30, it may nonetheless occur during normal operation. Continuing along the cutter bit 20, after the snap ring shaft 28, there is the snap ring groove 22 with a snap ring 29 in place. The snap ring 29 secures around the snap ring groove 22 and has an outer diameter that is greater than the opening diameter of the pocket adjacent to it. This configuration prevents the cutter bit from sliding out of the pocket during normal use. This is a fail-safe method for retaining the cutter bit to the host tool.

The split wear ring enables the efficient use of the cutter bit while reducing the wear on the pocket. The split wear ring moves relatively little, if at all, in relation to the inner surface of the pocket. However, the remaining portion of the cutting bit, including the tooth and relieved shank surface, are allowed to rotate. This results in a tooth that is worn down more evenly during use. The relieved shank surface and the split wear ring will wear down as well, but they wear down at a much lower rate in most cases than the tooth portion. Most importantly, there is a significant reduction in wear of the inner surface of the pocket as the majority of the friction from the rotating cutter bit occurs between the relieved shank surface and split wear ring. Therefore, the current invention enables users of the disclosed cutter bit to easily and effectively have rotating cutter bits that wear evenly and replace easily while reducing the need to replace and/or repair the pocket of the host tool.

FIG. 10 is a side view of another embodiment of invention where there are two wear rings. This embodiment is very similar to that of the single wear ring cutter bits illustrated and described in the other figures, except that in this embodiment there is a second wear ring 25 that fits over the snap ring shaft 28.

Installation and removal of the cutter bit is a relatively easy process that can be performed in the field. To install the cutter bit into a pocket, the shank of the cutter bit is inserted into the pocket. As the cutter bit is pressed into the pocket, the tapered edges of the split wear ring engage the outer surface of the pocket. This causes the split wear ring to compress slightly as the cutter bit continues into the pocket. Once the cutter bit is fully inserted into the pocket, the flange protects the outer surface of the pocket and the shank with the snap-ring shaft extends beyond the other side of the pocket. A snap-ring is then secured to the snap-ring shaft to prevent the cutter bit from becoming dislodged from the pocket. When the cutter bit needs to be replaced, the snap-ring is removed and the cutter bit is forced from the pocket. This can be achieved by applying force to the end of the shank that extends axially through the pocket until the cutter bit is removed from the pocket.

It should be understood that while the preferred embodiments of the invention are described in some detail herein, the present disclosure is made by way of example only and that variations and changes thereto are possible without departing from the subject matter coming within the scope of the following claims, and a reasonable equivalency thereof, which claims I regard as my invention.

All of the material in this patent document is subject to copyright protection under the copyright laws of the United States and other countries. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in official governmental records but, otherwise, all other copyright rights whatsoever are reserved. 

1. A cutter bit comprising a relieved shank surface, a retaining shoulder, and a split wear ring, where the split wear ring is axially mounted to and substantially surrounds the relieved shank surface, where the split wear ring has a resting outer diameter, where the retaining shoulder has an outer diameter, where the resting outer diameter of the split wear ring is greater than the outer diameter of the retaining shoulder.
 2. The cutter bit of claim 1, further comprising a snap ring shaft and a snap ring groove, where the snap ring shaft has an outer diameter, where the outer diameter of the snap ring shaft is less than the outer diameter of the retaining shoulder.
 3. The cutter bit of claim 1, further comprising a flange.
 4. The cutter bit of claim 3, where the flange has an outer diameter, where the outer diameter of the flange is greater than the resting outer diameter of the split wear ring.
 5. The cutter bit of claim 1, where the split wear ring comprises a tapered edge, where the tapered edge is adjacent to the retaining shoulder.
 6. The cutter bit of claim 1, additionally comprising an additional split wear ring.
 7. A cutter bit system comprising a cutting bit and a pocket, where the cutter bit comprises a relieved shank surface, a retaining shoulder, and a split wear ring, where the split wear ring is axially mounted to and substantially surrounds the relieved shank surface, where the split wear ring has a resting outer diameter, where the retaining shoulder has an outer diameter, where the resting outer diameter of the split wear ring is greater than the outer diameter of the retaining shoulder, where the split wear ring can be compressed thereby reducing its outer diameter, where the pocket has an inner surface, where the inner surface of the pocket has a first inner diameter that is greater than the outer diameter of the retaining shoulder of the cutter bit and less than the resting outer diameter of the split wear ring.
 8. The cutter bit system of claim 7, where the cutter bit relieved shank surface, retaining shoulder, and split wear ring are secured within the inner surface of the pocket.
 9. The cutter bit system of claim 7, where the cutter bit further comprises a snap ring shaft and a snap ring groove, where the snap ring shaft has an outer diameter, and where the inner surface of the pocket has a second inner diameter that is less than the first inner diameter, where the second inner diameter is greater than the outer diameter of the snap ring shaft.
 10. The cutter bit system of claim 9, where the cutter bit further comprises a snap ring, where the snap ring secures the cutter bit to the pocket.
 11. The cutter bit system of claim 7, where the cutter bit further comprises a flange, where the flange has an outer diameter, where the outer diameter of the flange is greater than the resting outer diameter of the split wear ring.
 12. The cutter bit system of claim 11, where the outer diameter of the flange is greater than the first inner diameter of the pocket.
 13. The cutter bit system of claim 7, where the split wear ring comprises a tapered edge, where the tapered edge is adjacent to the retaining shoulder.
 14. A method of using a cutter bit comprising the steps of obtaining a cutter bit, where the cutter bit comprises a relieved shank surface, a retaining shoulder, a flange, and a split wear ring, where the split wear ring is axially mounted to and substantially surrounds the relieved shank surface, where the split wear ring has a resting outer diameter, where the retaining shoulder has an outer diameter, where the resting outer diameter of the split wear ring is greater than the outer diameter of the retaining shoulder, where the split wear ring can be compressed thereby reducing its outer diameter, where the flange has an outer diameter, inserting the relieved shank surface, retaining shoulder, and split wear ring of the cutter bit into a pocket, where the pocket is secured to a host tool, securing the cutter bit to the pocket, using the host tool with the pocket and cutter bit to dislodge and/or break apart material where the pocket has an inner surface, where the inner surface of the pocket has a first inner diameter that is greater than the outer diameter of the retaining shoulder of the cutter bit and less than the resting outer diameter of the split wear ring, where the outer diameter of the flange is greater than the first inner diameter of the pocket.
 15. The method of claim 14, where the insertion of the cutter bit into the pocket causes the split wear ring to compress.
 16. The method of claim 14, where the split wear ring has an inner diameter, where the relieved shank surface has an outer diameter, where the inner diameter of the split wear ring after insertion into the pocket is greater than the outer diameter of the relieved shank surface.
 17. The method of claim 14, where the cutter bit rotates relative to the pocket during use, and where the relieved shank surface rotates relative to the split wear ring, thereby reducing the wearing of the inner surface of the pocket from the rotation of the cutter bit.
 18. The method of claim 14, where the cutter bit further comprises a snap ring shaft and a snap ring groove, where the snap ring groove in conjunction with a snap ring secures the cutter bit to the pocket.
 19. The method of claim 14, where the split wear ring comprises a tapered edge, where the tapered edge is adjacent to the retaining shoulder, where the tapered edge aids in the insertion of the split wear ring into the pocket.
 20. The method of claim 14, further comprising the step of removing the cutter bit from the pocket. 